Hand-held instrument for dental or surgical use

Abstract

A hand-held instrument, for dental or surgical use, intended to rotate a rectilinear detachable tool ( 13 ) includes a tubular sheath ( 1 ); a hollow shaft ( 3 ) rotatably mounted inside the sheath with an upstream portion ( 5 ) and a downstream portion ( 6 ) which in turn includes an upstream portion ( 11 ) partially clamped around the upstream portion ( 5 ) of the shaft and a downstream portion ( 12 ) of which the inside diameter substantially matches the outside diameter of the tool ( 13 ); a clamp ( 14 ) rigidly rotationally connected to the shaft ( 3 ) but movable along the axis thereof, which clamp is placed inside and concentric with the upstream portion ( 5 ) of the shaft; and elements for moving the clamp ( 14 ) longitudinally so that the jaws ( 17 ) thereof penetrate under the upstream portion ( 5 ) of the shaft ( 3 ) thereby gripping the tool.

1. A hand-held instrument, for dental or surgical use, intended to rotate, at high speed, a detachable rectilinear tool whereof the end constitutes a bur or similar member, wherein said instrument comprises:
 a tubular sheath having a longitudinal axis, 
 a first hollow shaft, having the same axis, mounted to rotate inside said tubular sheath, the first hollow shaft comprising: 
 an upstream part of the first hollow shaft, and 
 a downstream part of the first hollow shaft, 
 the downstream part of the shaft itself comprising i) an upstream part partially clasping the upstream part of the first hollow shaft and ii) a downstream part whereof the internal diameter corresponds substantially to an external diameter of the tool, 
 a clamp integral in rotation with said first hollow shaft but movable along said axis and arranged inside the upstream part of the first hollow shaft, concentrically to the first hollow shaft, said clamp existing, in its an upstream part, in the form of a second hollow shaft having an internal diameter corresponding substantially to the external diameter of the tool and which, beyond this, is extended by several elastically deformable jaws designed to grip the tool, and 
 means for moving said clamp longitudinally in the upstream direction such that its jaws penetrate under the upstream part of the first hollow shaft and thus ensure gripping of the tool, and in the downstream direction such that the jaws escape said upstream part and thus ensure releasing of the tool, 
 wherein the end of said jaws constitutes a wedge having a conical profile whereof the thickness increases in the downstream direction and wherein the upstream part of the first hollow shaft is extended, without being part of it, by an independent ring ensuring gripping of the clamp, said ring having a conical internal profile which corresponds to the conical profile of the wedges, a constant external diameter of said ring being slightly smaller than an external diameter of the upstream part of the first hollow shaft so as to offer it a clearance which causes it to float between the wedges and the upstream part of the downstream part of the first hollow shaft, 
 wherein upstream designates an end of the instrument from which the tool is driven in rotation and downstream designates an end bearing the operative tip of the tool. 
 
     
     
       2. The instrument according to  claim 1 , wherein said tubular sheath has a slender nose forming an angle from 5° to 10° providing the operator with the best possible view of the operation area. 
     
     
       3. The instrument according to  claim 2 , wherein said first hollow shaft is mounted in rotation inside the tubular sheath with the help of a bearing located, in the nose of the tubular sheath, downstream of the clamp, toward the upstream end of the downstream part of the downstream part of the first hollow shaft. 
     
     
       4. The instrument according to  claim 1 , wherein said means for moving said clamp longitudinally comprise a sleeve for screwing and unscrewing on the upstream part of the tubular sheath and ensuring the longitudinal movement of the clamp. 
     
     
       5. The instrument according to  claim 2 , wherein said means for moving said clamp longitudinally comprise a sleeve for screwing and unscrewing on the upstream part of the tubular sheath and ensuring the longitudinal movement of the clamp. 
     
     
       6. A hand-held instrument, for dental or surgical use, intended to rotate, at high speed, a detachable rectilinear tool whereof the end constitutes a bur or similar member, the hand-held instrument comprising:
 a tubular sheath ( 1 ) having a longitudinal axis (AA) and terminating in a nose ( 2 ); 
 a first hollow shaft ( 3 ), having the same longitudinal axis (AA), mounted to rotate inside said tubular sheath ( 1 ), the first hollow shaft ( 3 ) comprised of i) an upstream part ( 5 ), and ii) a downstream part ( 6 ) overlapping and abutting against the upstream part ( 5 ), 
 the downstream part ( 6 ) of the first hollow shaft ( 3 ) comprising i) an upstream cylindrical part ( 11 ) partially clasping the upstream part ( 5 ) of the first hollow shaft ( 3 ) and ii) a downstream cylindrical part ( 12 ) with an internal diameter corresponding substantially to an external diameter of the tool, in use, the downstream cylindrical part ( 12 ) being immediately adjacent to the external surface of the tool; 
 a clamp ( 14 ) concentrically inside the upstream part of the first hollow shaft ( 3 ) and integral in rotation with the first hollow shaft ( 3 ) and longitudinally movable along said axis (AA), the clamp comprising i) an upstream part in the form of a second hollow shaft ( 15 ) having an internal diameter corresponding substantially to the external diameter of the tool and ii) a downstream part in the form of plural elastically deformable jaws ( 17 ) adapted to grip the tool and including an end defined by a wedge ( 18 ) having a conical profile with thickness increasing in the downstream direction; and 
 a bar ( 9 ) moved under action of an external sleeve ( 10 ) for moving said clamp ( 14 ) longitudinally in the upstream direction such that the jaws ( 17 ) penetrate under the upstream part ( 5 ) of the first hollow shaft ( 3 ) and thus ensure gripping of the tool, and in the downstream direction such that the jaws ( 17 ) escape said upstream part ( 5 ) of the first hollow shaft ( 3 ) and thus releasing of the tool, wherein, 
 the deformable jaws including an end defined by a wedge ( 18 ) having a conical profile with thickness increasing in the downstream direction, 
 the upstream part of the first hollow shaft is adjacent an independent ring ensuring gripping of the clamp, 
 the independent ring having a conical internal profile corresponding to the conical profile of the wedges, 
 the upstream part of the first hollow shaft being extended, without being part of the first hollow shaft, by the independent ring, 
 a constant external diameter of the ring being slightly smaller than an external diameter of the upstream part of the first hollow shaft so as to float between the wedges and the upstream part of the downstream part of the first hollow shaft, 
 wherein upstream designates an end of the instrument from which the tool is driven in rotation and downstream designates an end bearing the operative tip of the tool. 
 
     
     
       7. The instrument according to  claim 6 , wherein the nose forms an angle from 5° to 10° . 
     
     
       8. The instrument according to  claim 7 , further comprising:
 a bearing in the nose of the tubular sheath and located downstream of the clamp, 
 wherein said first hollow shaft is mounted in rotation inside the tubular sheath with the help of the bearing. 
 
     
     
       9. The instrument according to  claim 6 , wherein said clamp is moved longitudinally by screwing and unscrewing the external sleeve on the upstream part of the tubular sheath. 
     
     
       10. The instrument according to  claim 6 , wherein the bar is a transverse bar ( 9 ) axially movable under action of the external sleeve ( 10 ), which sleeve ( 10 ) is screwed and unscrewed on the upstream part of the sheath. 
     
     
       11. The instrument according to  claim 7 , wherein, the bar is a transverse bar configured so that screwing and unscrewing the external sleeve on the upstream part of the tubular sheath and axially moves the transverse bar ( 9 ). 
     
     
       12. The instrument according to  claim 1 , wherein the downstream part of the first hollow shaft extends downstream of the end of jaws defined by wedge. 
     
     
       13. The instrument according to  claim 6 , wherein the downstream part ( 6 ) of the first hollow shaft ( 3 ) extends downstream of the downstream part of the clamp ( 14 ), including the plural elastically deformable jaws ( 17 ) the end defined by the wedge ( 18 ). 
     
     
       14. The instrument according to  claim 1 , wherein,
 said upstream part of the first hollow shaft surrounds the clamp, 
 the downstream part of the first hollow shaft partially surrounds the upstream part of the first hollow shaft, concentrically to the upstream part of the first hollow shaft, and 
 the downstream part forms a barrel for the passage of the shank of the tool. 
 
     
     
       15. The instrument according to  claim 6 , wherein,
 said upstream part ( 5 ) of the first hollow shaft ( 3 ) surrounds the clamp ( 14 ), 
 the downstream part ( 6 ) of the first hollow shaft ( 3 ) partially surrounds the upstream part ( 5 ) of the first hollow shaft ( 3 ), concentrically to the upstream part ( 5 ) of the first hollow shaft ( 3 ), and 
 the downstream part ( 6 ) forms a barrel for the passage of the shank ( 13 ) of the tool.